Fountain pen



FIG. 1 is a perspective view of the fountain pen showing my new design in closed position, the lettering shown in dotted lines is not claimed as part of my design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a front elevational view with the cap removed, the nib is shown in dotted lines and is not claimed as part of my design;

FIG. 6 is a side elevational view of the cap of the fountain pen showing my new design; and,

FIG. 7 is a bottom view of the cap. 

The ornamental design for a fountain pen, as shown and described. 